Paper punches of the type in which a plurality of punching elements perforate the paper inserted in the punch gap and pass through associated punch or die holes in the punch body are well known and are widely used in practically every office.
It is often desired to punch different numbers of holes, e.g., to provide two holes or three holes, or more, or to have the holes differently spaced apart so that the perforated paper will be suitable for different types of loose-leaf binders or for different standard types of binder clips, conventionally found in business offices.
For this purpose, punches have been developed in which the punching elements which produce the holes or perforations are constructed to be selectively engaged and disengaged. Constructions of this type are shown, for example, in Allen, U.S Pat. No. 746,625; Finley, U.S. Pat. No. 1,655,315; and Semerjian et al, U.S. Pat. No. 4,449,436.
To facilitate the binding of punched or perforated sheets in files or binders fasteners of a kind commonly used to bind sheets in a file are conventionally furnished in a plurality of standard sizes: that is, the fasteners are formed with prongs or like elements, spaced apart at different distances to be extended through holes punched in the paper sheets. Other kinds of file folders, such as for example, those having ring or post binders, often have differently spaced rings or posts, thus also necessitating selected variations in the spacing of the perforation in the sheets to be filed in the folders.
Known types of paper punches commonly used to perforate sheets to receive or be received in binders or folders frequent have punch elements which may be selectively engaged or disengaged. Such paper punches having selectively engageable punches frequently embody complicated and costly constructions. Furthermore, they are often incapable of simple and easy manipulation and operation by inexperienced operators and, hence, are unsuited for general office use.